.select {
  background-image: linear-gradient(45deg, transparent 50%, currentColor 50%),
    linear-gradient(135deg, currentColor 50%, transparent 50%);
  background-position: calc(100% - 20px) calc(1px + 50%),
    calc(100% - 16px) calc(1px + 50%);
  background-size: 4px 4px, 4px 4px;
  background-repeat: no-repeat;
}
